If you look at your bulb's it should say on them, also is it a one bulb fixture or are there multiple?

As for as the water changes and algae goes you NEED to change your water more often. I recommend changing atleast 25% a week but if that's not possible change 50% every two weeks. The less often you change your water the higher your nitrates get. The higher your nitrates get the more nutrients the algae has to grow and spread!